When standard treatments failed, a decades-old heart medication gave a newborn with a rare lymphatic disorder a new chance at life.
This is the story of a baby boy born at 36 weeks with severe breathing issues caused by massive fluid buildup in his chest. Diagnosed with a condition called congenital chylothorax, his lungs were filled with a milky fluid called chyle, leaking from damaged lymphatic vessels.
Doctors tried everything—chest tubes, specialized nutrition, octreotide, steroids—but the chyle kept returning.
After eight exhausting weeks in the neonatal ICU, the care team turned to propranolol, a medication typically used to treat high blood pressure. Within days, the chyle started to disappear. Within weeks, the baby could breathe more easily and began to thrive.
The Diagnosis: A Rare Genetic Mutation
Prenatal scans had hinted something was wrong, but it wasn’t until genetic testing revealed a PIEZO-1 mutation that the puzzle pieces came together. This mutation can cause complex lymphatic anomalies, which disrupt the body’s ability to move and regulate fluid.
In this baby’s case, the mutation led to severe, persistent leakage of chyle into the chest—a dangerous condition that can result in respiratory failure, poor nutrition, and even immune system dysfunction.
When Everything Else Failed
Initial treatments included:
- Chest drainage with tubes on both sides
- Medium-chain triglyceride (MCT) formula to reduce lymph flow
- Total parenteral nutrition (TPN) to support growth
- High-dose octreotide and steroids to control inflammation and leakage
These helped reduce the output slightly, but not enough. The child continued to lose vital nutrients and fluids.
That’s when the team reintroduced propranolol at a cautious dose. This time, they increased it slowly and monitored for side effects like low blood pressure or low blood sugar.
A Remarkable Turnaround
Within one week of restarting propranolol:
- Chylous fluid output dropped dramatically
- Chest X-rays showed shrinking pleural effusions
- The remaining chest tube was removed
When the propranolol dose was briefly reduced, the fluid returned. But once restored to a higher dose, the improvement returned—and held steady. The baby was eventually discharged on oral propranolol and MCT-based formula, with no recurrence at follow-up.
Why Did Propranolol Work?
- Although propranolol is best known as a heart medication, it has other powerful effects:
- It reduces vascular endothelial growth factor (VEGF), a key driver of lymphatic vessel overgrowth
- It promotes cell death in abnormal vessels
- It may even reduce activity in the mTOR pathway, which is often overactive in lymphatic anomalies
This makes propranolol a promising treatment for lymphatic leakage disorders, especially when standard options fall short.
What This Means for Families
- Propranolol is a well-known and relatively safe drug when used with careful monitoring
- Genetic testing matters: Identifying a PIEZO-1 mutation helped guide treatment
- Early and persistent intervention is key to avoiding long-term complications
This case shows that even in the most difficult neonatal cases, new hope can emerge from old medicines. Authors indicated that a large, adequately powered multi-centre study is essential to establish the dose-response relationship, efficacy, and safety of propranolol in the context of congenital refractory chylothorax. More research is needed, but propranolol could become a valuable option for babies battling congenital chylothorax due to lymphatic anomalies.
Propranolol: A novel therapy for neonatal chylothorax secondary to congenital lymphatic anomaly. Aashish Gupta, Mary Woodward, Emer Finan, and Bonny Jasani Journal of Clinical Insights in Neonatology 2025 1:1, 28-32
